/*
 *  SableJBDD, a Java Binary Decision Diagram package.
 *  Copyright (C) 2003  Feng Qian
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
//$Id: BddCache.java,v 1.1 2004/03/12 00:15:29 fqian Exp $

package SableJBDD.bdd.internal;

import SableJBDD.bdd.JBddConstants;
import SableJBDD.bdd.JBddNode;

import SableJBDD.cache.TripleIntKeyCache;

import SableJBDD.bdd.util.HashFunction;
import SableJBDD.bdd.util.Profiling;

import java.io.PrintStream;

/**
 * An abstract cache uses three integers as the key.
 *
 * @author Feng Qian
 */
public interface BddCache extends Profiling{
  /**
   * Looks up a bdd node by three unique keys, f, g, and h could be a bdd
   * variable, a bdd node, or operations.
   * Returns null if no such node exists.
   */
  public JBddNode lookup(Unique f, Unique g, Unique h);

  /**
   * Puts a bdd node into the cache. 
   */
  public void put(Unique f, Unique g, Unique h, JBddNode node);

  /**
   * Resets the cache.
   */
  public void reset();

  /** Returns the number of entries. */
  public int size();
}
